As a conventional technology involving an electric motor for driving a hydraulic pump, one disclosed in Patent Document 1 can be mentioned. Although this conventional technology is applied to a hydraulic excavator rather than a dump truck to which the present invention is applied, it is provided with an engine, a generator for outputting electricity corresponding to a rotation speed of the engine, an electric motor to which the electricity is fed from the generator via an inverter, a hydraulic pump drivable by the electric motor, hydraulic actuators operable by pressure oil delivered from the hydraulic pump, and control valves for controlling flows of pressure oil to be fed from the hydraulic pump to the hydraulic actuators.
The engine and the generator are arranged as an integrated combination, while the electric motor and the hydraulic pump are arranged as an integrated combination. These integrated combinations are located apart from each. The conventional technology, therefore, has a merit in that the engine and the hydraulic pump are not connected directly and the hydraulic pump can hence enjoy a greater degree of freedom as to its installation position.
Patent Document 1: JP-A-2001-11888